2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Another OMP pre-mix? (confused self in search)

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Old Oct 31, 2011 | 06:28 PM
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From: Cape Canaveral FL
Another OMP pre-mix? (confused self in search)

90 vert. Searched for hours but never was 100% clear on this. Can this be done? 3 questions:

1) I get the RTek chip for the ECU for OMP delete--assuming ECU is not fried yet
2) Leave OMP 'as is' installed in the car with injection lines, nozzles, etc. in place as well as all electrical connections, etc. In other words, leave factory installed configuration in place
3) Start pre-mix 1 oz/gal 2-stroke oil in gas tank

Found this in search which seems helpful in someone troubleshooting a failed OMP:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/s5-mop-ecu-failure-diagnosis-710938/
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Old Oct 31, 2011 | 06:35 PM
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From: tulsa,ok.
If you RTEK'ed then followed that w/premixing there would be no need for the OMP thus if you so chose to do so you could remove the pump and put a block off plate in its place or do as you stated.
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Old Oct 31, 2011 | 06:42 PM
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What? So if you want to start premixing, you just can't disconnect the OMP and start premixing? You have to update the ECU, too?
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Old Oct 31, 2011 | 06:42 PM
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Thanks, I did see that but I was hoping to leave everything in place as much as possible. At least for now.
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Old Oct 31, 2011 | 06:45 PM
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Originally Posted by Casual_John
What? So if you want to start premixing, you just can't disconnect the OMP and start premixing? You have to update the ECU, too?
I thought I made that clear. See Question 1) "I get the RTek chip for the ECU for OMP delete--assuming ECU is not fried yet"
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Old Oct 31, 2011 | 10:34 PM
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From: And the horse he rode in on...
Originally Posted by Casual_John
What? So if you want to start premixing, you just can't disconnect the OMP and start premixing?
No.

Originally Posted by Casual_John
You have to update the ECU, too?
Yes
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Old Oct 31, 2011 | 10:34 PM
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Originally Posted by Casual_John
What? So if you want to start premixing, you just can't disconnect the OMP and start premixing? You have to update the ECU, too?
John,you can't just disconnect the OMP on an s5 and premix.
The OMP is hooked to the ECU and if that signal gets "detached" then the Car goes into limp mode.
That is part of the New S5 technology,compared to the Mechanical omp on s4's..lol!
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Old Oct 31, 2011 | 10:50 PM
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From: And the horse he rode in on...
Originally Posted by jdonnell
90 vert. Searched for hours but never was 100% clear on this. Can this be done? 3 questions:

1) I get the RTek chip for the ECU for OMP delete--assuming ECU is not fried yet
2) Leave OMP 'as is' installed in the car with injection lines, nozzles, etc. in place as well as all electrical connections, etc. In other words, leave factory installed configuration in place
3) Start pre-mix 1 oz/gal 2-stroke oil in gas tank

Found this in search which seems helpful in someone troubleshooting a failed OMP:
https://www.rx7club.com/showthread.php?t=710938
That is the best most comprehensive thread. Quit driving the car or it WILL burn out. You can also open up your ECU and examine the circuits for visual damage. Mine looked exactly like the burned ECU in that thread.

There is some discussion that you could have an ECU rTeK chipped even if it is burned out, since supposedly only the MOP output drive circuits are damaged. Then disable the MOP in software and it works for premixing.

Discuss it with Rtek.
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Old Nov 1, 2011 | 01:16 AM
  #9  
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From: Perth, WA, OZ
the ecu controls the volume through the pump
if you have rtek then it no longer will alter the pumps output according to load
it will not limp the engine either cause it sees it no longer will interpret the not moving eomp as a fault

the eomp that is physically on the side of the engine will STILL add oil to the engine
it will do so at a fixed rate depending on where the stepper motor parked when it was disconnected

you can simply take off the stepper motor cover and wind it to a fixed position you are happy with
you can also simply take out the actuator spindle and just replace it with a spacer of your desire

the pump will work at the fixed rate per engine revolution , and you should supplement this with a smaller amount of premix

this gives best of both worlds,, give economy in the premix ratio ( which can now be 200 or 250:1 )
and yet have redundancy if you forget to top up the petrol with 2 stroke ,, and better wet the hot spot in middle of apex seal
( and that is the reason mazda went to so much effort to stick on the housing squirts in the first place )
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Old Nov 1, 2011 | 11:19 AM
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Originally Posted by jackhild59
No.
Why?

Originally Posted by jackhild59
Yes.
Why?

Originally Posted by misterstyx69
John,you can't just disconnect the OMP on an s5 and premix.
The OMP is hooked to the ECU and if that signal gets "detached" then the Car goes into limp mode.
That is part of the New S5 technology,compared to the Mechanical omp on s4's..lol!
And now we know.
Thanks for explaining.
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